How to trigger the Dark Wanderer's three secrets in this week's tavern brawl?

There are a total of 10 possible secrets, 3 of which are randomly chosen each game. Those are:

• Visions of the Amazon - Secret: When your opponent summons a minion with Battlecry, Summon a Mirror Image for both players.
• Visions of the Assassin - Secret: When your opponent summons a minion with Stealth, All minions equip a dagger.
• Visions of the Barbarian - Secret: When your opponent summons a minion with Charge, THUNDER FURY!
• Visions of the Crusader - Secret: When your opponent summons a minion with Taunt, change all minions' attacks to 1.
• Visions of the Necromancer - Secret: When your opponent summons a minion with Deathrattle, destroy it.
• Visions of the Sorcerer - Secret: When your opponent summons a minion with Spell Damage, Summon 2 Guardians.
• Visions of Fate - Secret: When your opponent takes lethal damage... save him.
• Visions of Hate - Secret: When both heroes have 15 or less Health, BRAWL!
• Visions of Valor - Secret: When your opponent summons a Legendary minion, give all minions Windfury.
• Visions of Knowledge - Secret: When your opponent's hand has 9 or more cards, reduce the cost of all cards in both hands to (1).

Source: http://www.hearthpwn.com/news/2134-the-dark-wanderer-is-this-weeks-tavern-brawl-and